The present invention relates generally to agricultural harvesting machines, and more specifically, to operator presence devices which are designed to interrupt drive to a harvesting unit or other equipment when the operator leaves the operating station.
In order to help prevent exposure of a user of a selfpropelled agricultural harvesting implement to an operating harvesting unit, an operator presence system including a seat switch is sometimes utilized, under limited circumstances, to terminate the power input to the harvesting unit if the operator leaves his seat. Although several operator presence switch systems are available, most suffer from one or more disadvantages. Some systems actually stop the engine when the operator moves from a preselected position, and the momentum of the engine will maintain the harvesting units operational for a short period after cutoff. Unwanted and annoying stoppage can also occur during transporting of the vehicle if an operator shifts his position or is momentarily off the seat while driving the vehicle. There are times when the operator desires to run the harvesting unit slowly for servicing or observation, and, with one of the above mentioned systems, such an operation requires two people, one to operate the machine from the operator station and another to view the harvesting mechanism. Finally, reliability of the system under various operating conditions, is another disadvantage of some of the existing operator presence switch systems.